Tags

membrane

1. A thin, pliable layer of tissue that lines a tube or cavity, covers an organ or structure, or separates one part from another. 2. A very thin sheet of polymer, ceramics, glass, or metal.

alveolocapillary membrane

The membrane through which gases must pass as they diffuse from air to blood (oxygen) or blood to air (carbon dioxide), including the alveolar fluid and surfactant, cell of the alveolar wall, interstitial space (tissue fluid), and cell of the capillary wall. SYN: SEE: respiratory membrane

ALVEOLOCAPILLARY MEMBRANE

arachnoid membrane

The delicate middle membrane of the three meninges, which enclose the brain and spinal cord. The arachnoid membrane is 5-6 cells thick. It is adherent to the inner surface of the dura by dural border cells. It is connected to the pia mater by a spiderweb of thin connections, owing to their common embryological origin as the leptomeninges. The space between the arachnoid and pia (the subdural space) is filled with cerebrospinal fluid. SYN: SEE: arachnoid; SEE: arachnoid mater

atlanto-occipital membrane

A single midline ligamentous membrane that extends from the arch of the atlas to the borders of the foramen magnum.

basement membrane

A two-part extracellular membrane found at the interface between some tissues, e.g., skin and dermis. The basement membrane is made of a basal lamina along the cell surfaces, coated by a stronger collagen-rich layer (reticular lamina).

basilar membrane

The membrane extending from the tympanic lip of the osseous spiral lamina to the crest of the spiral ligament in the cochlea of the ear. It separates the tympanic canal from the cochlear duct and supports the organ of Corti. illus. under SEE: organ of Corti

black membrane

An artificially constructed membrane made of lipids arranged in a bilayer.

Demours membrane

Descemet membrane

diphtheritic membrane

dural membrane

egg membrane

Any of the protective membranes or envelopes enclosing an ovum. It may be primary (formed by egg itself, as in vitelline membrane), secondary (formed by follicle cells, as in zona pellucida), or tertiary (formed by oviduct or uterus, as in albumin and shell of hen's egg).

elastic membrane

Any of several membranes formed of elastic connective tissue fibers.

enamel membrane

epiretinal membrane

A membrane formed from excessive proliferation of retinal pigment epithelial cells and extracellular proteins on the retinal surface. This condition, which can distort vision, is typically found in people over 50. Marked visual blurring caused by epiretinal membranes occurs in macular pucker.SEE: macular pucker

external limiting membrane

1. The outer membrane of the embryonic neural tube. 2. The membrane in the retina of the eye through which the receptor portions of the rods and cones protrude.

false membrane

A membrane of fibrinous exudate on a mucous surface of a membrane, as in croup or diphtheria. SYN: SEE: croupous membrane

fenestrated membrane

A membrane possessing minute round or oval openings. It is found in the tunica intima and tunica media of medium-sized and large arteries.

fetal membrane

Any of the membranes that protect and support the embryo and provide its nutrition, respiration, and excretion. The structures are the yolk sac, allantois, amnion, chorion, decidua, and placenta.

fibrous membrane

A membrane composed entirely of fibrous connective tissue. Examples include the fasciae, aponeuroses, perichondrium, periosteum, dura mater, and the capsules of some organs.

glassy membrane

1. The transparent membrane that separates membrana granulosa from the theca of the graafian follicle. 2. The internal membrane of a hair follicle separating the epithelial and connective tissues.

glial cell membrane

An extremely delicate membrane, formed of foot plates of astrocytes, that surrounds all the blood vessels in the brain, spinal cord, and the lining of the pia mater, separating these vessels from the nervous tissue proper. This membrane is thought to be one of the components of the blood-brain barrier.

medullary membrane

mucous membrane

Any of the membranes that line passages and cavities communicating with the atmosphere outside the body. They consist of epithelium, a basement membrane, and an underlying layer of connective tissue (lamina propria). Mucus-secreting cells or glands are usually present in the epithelium but may be absent. Mucous membranes and the skin prevent the entry of pathogens. Some mucosal surfaces in the digestive tract have special characteristics that tend to repel or kill organisms, such as the extremely high acid level on the mucosa of the stomach. Others are normally colonized with commensal organisms that discourage the growth of pathogens.

nasal mucous membrane

The mucosa lining the nasal cavity and characterized by pseudostratified ciliated columnar epithelium with goblet cells.

olfactory membrane

oral membrane

oronasal membrane

A double epithelial membrane separating the nasal pits from the embryonic oral cavity.

otolithic membrane

A gelatinous membrane containing otoconia or otoliths, found on the surface of maculae in the inner ear.

palatal mucous membrane

The membrane of the mouth on the hard and soft palates. The hard palate has heavily keratinized epithelium and copious mucous glands or fat in the submucosa. The mobile soft palate contains muscle in addition to mucous glands, and is much less keratinized on the surface.

Ruysch membrane

schneiderian membrane

Schwann membrane

selectively permeable membrane

A membrane that allows one substance, such as water, to pass through more readily than another, such as salt or sugar.

semipermeable membrane

A membrane that allows passage of water but not of substances in solution. SEE: osmosis

serous membrane

A membrane consisting of mesothelium lying on a thin layer of connective tissue that lines the closed cavities (peritoneal, pleural, and pericardial) of the body and is reflected over the organs in the cavity. Serous fluid, similar to lymph, decreases friction between the two layers.

Shrapnell membrane

submucous membrane

synovial membrane

The membrane lining the capsule of a joint and secreting synovial fluid. The synovial membrane is pink, smooth, and shiny and is made of an intima lining a stronger, vascular fibrous membrane. The intima contains synoviocytes (fibroblast- and macrophage-like cells), which remove debris from the synovial fluid and synthesize some of the mucin (specifically, hyaluronic acid) of the synovial fluid. Most of the synovial fluid is filtered from the blood vessels of the outer fibrous layer of the synovial membrane. SYN: SEE: synovium

tectorial membrane

The jelly-like membrane projecting from the vestibular lip of the osseous spiral lamina and overlying the spiral organ of Corti of the inner ear.

thyrohyoid membrane

The membrane joining the hyoid bone and the thyroid cartilage.

tympanic membrane

The three-layered membrane at the inner (medial) end of the external auditory canal, forming the lateral boundary of the middle ear cavity. The outer layer of the tympanic membrane is keratinized skin, continuous with the skin lining the external ear canal. SYN: SEE: drum; SEE: eardrumSEE: ear thermometry; SEE: tympanum

unit membrane

The phospholipid bilayer first described as the typical cell membrane, then as the membrane of intracellular structures.

vapor-permeable membrane

A membrane, usually transparent, that is permeable to oxygen and water vapor. It may be prepared with an adhesive backing that will stick only to dry skin. This type of membrane has been used in covering wounds. The membrane must be applied properly without wrinkles and changed as often as necessary to prevent excess accumulation of fluid and bacteria under it.

vestibular membrane

The membrane in the cochlea of the inner ear that separates the cochlear duct from the vestibular canal.

vestibular mucous membrane

The mucosa of the oral vestibule with its nonkeratinized stratified squamous epithelium, elastic lamina propria, and seromucous labial glands.